1. Field of the Invention
The present invention generally relates to a three-dimensional image display apparatus capable of displaying medical images such as X-ray CT (computerized tomography) images and MRI (magnetic resonance imaging) images as 3-D images. More specifically, the present invention is directed to a 3-D image display apparatus that immediately forms 3-D images, e.g., a surface image of a patient, from a plurality of X-ray CT images by simply manipulating a positioning encoder.
2. Description of the Related Art
Generally speaking, in conventional 2-dimensional X-ray CT imaging apparatuses, the positioning encoder unit, for instance, a rotary encoder is employed so as to set the window level/width of the acquired two-dimensional CT image with respect to the CT value thereof. Furthermore, to display the three-dimensional image, e.g., surface images of organs, bones and blood vessels of a patient, by these CT imaging apparatuses, a plurality of acquired CT image data must be processed by way of the known voxel method, and also both the upper and lower threshold levels must be determined in order to extract each CT value of the relevant CT imaging region by operating the keyboard. In other words, to perform the voxel method for the plurality of CT image data, such a threshold level setting operation must be carried out with respect to all of the acquired CT images, which may require cumbersome keyboard operations.
Moreover, the function of the positioning encoder employed in the conventional X-ray CT imaging apparatus is to merely determine the CT value of the respective two-dimensional CT images, not to determine the threshold levels of the 3-dimensional image.
As a result, since the voxel data must be formed for each of the acquired X-ray CT images, a lengthy waiting time is necessarily required for finally displaying the desired 3-D image. Moreover, when a sort of the desired 3-D image is varied from the bone to the organs, for example, this drawback, namely length waiting time, is further emphasized.
The present invention has been made in an attempt to solve the above-described drawbacks of the conventional 3-D image display apparatuses, and therefore has an object to provide a 3-D image display apparatus capable of readily changing the region of the object under medical examination to be imaged with a simple operation, and also of immediately displaying the 3-D image of the desirable imaging region.
Another object of the invention is to provide a 3-D image display apparatus employing a positioning encoder unit capable of determining the threshold levels of the 3-D image.